title: An effective real-time colorimeteric sensor for sensitive and selective detection of cysteine under physiological conditions.
abstract: In this contribution, a new, real-time and sensitive colorimetric sensor, di-N-methyl-N-hydroxyethylaniline squaraine (SQ), has been identified and synthesized for cysteine analysis based on its ΔA in neutral aqueous medium (pH ≈ 7.5). The proposed method was applied to analyse synthetic amino acid samples and human serum samples. The results show that the linear range of cysteine detection in aqueous medium at pH ≈ 7.5 is 10~700 nmol L(-1) with a correlation coefficient (R) of 0.9984 and a limit of detection (3σ, n = 20) of 3.9 nmol L(-1). The relative standard deviation (RSD) for cysteine detection was lower than 4.1% (n = 5). The proposed method possesses the advantages of simplicity, rapidity, high selectivity and sensitivity. This makes it possible, for the first time, the real-time detection of cysteine under normal physiological conditions.
authors.affiliation: College of Material Science and Engineering, Chemistry and Chemical Engineering & State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China.
authors.forename: Zhengquan
authors.initials: Z
authors.lastname: Yan
authors.forename: Shanyi
authors.initials: S
authors.lastname: Guang
authors.forename: Hongyao
authors.initials: H
authors.lastname: Xu
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Liu
mesh_terms: D000814:Aniline Compounds / Q000138:chemical synthesis*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D003124:Colorimetry / Q000295:instrumentation* / Q000379:methods*; D003503:Cyclobutanes / Q000138:chemical synthesis*; D003545:Cysteine / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010636:Phenols / Q000138:chemical synthesis*; D044967:Serum / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D003503:Cyclobutanes; D010636:Phenols; D013501:Surface-Active Agents; C559747:di-N-methyl-N-hydroxyethylaniline squaraine; D003545:Cysteine